A method for manufacturing a vertically integrated component having an MEMS element, a cap for the micromechanical structure of the MEMS element, and an ASIC substrate is discussed in US 2011/0012247 A1. The method provides that these three elements of the component are manufactured independently of one another and a separate starting substrate is provided for each element. The MEMS substrate is bonded to the ASIC substrate, which is already processed and optionally also structured. According to US 2011/0012247 A1, the processing of the MEMS substrate may take place either before or also only after the installation on the ASIC substrate, but must be completed upon the mounting of the cap substrate. The cap substrate is structured initially in any case, before it is mounted over the micromechanical structure of the MEMS element. The cap substrate is also bonded on the ASIC substrate for this purpose.
The method allows cost-effective mass production of robust components having a micromechanical sensor function and an evaluation circuit, since not only the individual component elements—MEMS element, cap, and ASIC—are manufactured in the wafer composite here, but rather also their assembly is implemented at the wafer level to form a sensor component. The electrical testing of the MEMS functions and the ASIC functions and the balancing of the individual sensor components may also be carried out at the wafer level. This also contributes to a reduction of the manufacturing costs.
Some aspects of the method have certain disadvantages in practice. Thus, the use of three starting substrates during the manufacture of the three component elements causes a relatively high material and processing outlay. In addition, two bonding processes, which are independent of one another and are each relatively complex, must be carried out within the scope of the component assembly. Finally, it is also to be noted that the components thus manufactured have a comparatively large structural height.